Combination gyroplane

ABSTRACT

This invention relats to a combination gyroplane having a lockable rotor and rotor blades adapted to be retracted in the locked condition, comprising an equal number of rotor blades positioned in at least two planes offset with respect to each other with reference to the rotor axis, and means for maintaining the blade groups in operative position in a staggered arrangement and for causing the rotor blades of the groups to overlap for the retracting operation.

United States Patent Buchstaller [45] N 13, 1973 I {54] COMBINATION GYROPLANE 3,135,333 6/1964 Cruz 8! al. 416,143

3,369,610 2/1968 Dancik 416/143 [75] Inventor. (A;nton Buchstaller, Frledrichshafen, 2,405,777 8/1946 Buivid i 416,143 "many 2,665,859 1 1954 Papadakos.... 416/130 [73] Assignee: Dornier A.G., Friedrichshafen, xqsllskis rms y Bodensee Germany 2,658,575 10/1953 Stone 416/121 22 Filed; Oct 1970 3,370,809 2/1968 Leoni 244/7 R 3,096,041 7/1963 Cheeseman et al 244/7 R 211 App]. No.: 78,471

Primary Examiner-Everette A. Powell, Jr. {30] Foreign Application Priority Data Attorney-James E. Bryan Deo ZQ 1969 Germany ..P 19 63 931, 7

. [57] ABSTRACT [52] US. Cl 416/121, 416/ 143, 244/7 Tbi i wemipn rqlates to a ornbination gyroplane hav. [5 l l II"- Cl. a lockable rotor and rotor blads aaaptea of Search 30, tracted in the locked condition comprising an equal 19 244/7, 7 A number of rotor blades positioned in at least two planes offset with respect to each other with reference References Clted to the rotor axis, and means for maintaining the blade UNITED STATES PATENTS groups in operative position in a staggered arrange- 3,625.63! 12/1971 Covington 416 121 and for causing the rotor blades of the groups to 3,612,444 10 1971 Girard 416/143 Overlap for the retracting Operationv 3,133,715 5/1964 Grunfelder 416/143 12 Claims. 7 Drawing Figures H o E 1 76 r PATENTEDRUY 13 1913 SHEET 1 [IF 4 III I lull).

INVEN'IOI ANTON BUCHSTALLER FIG. 1

PATENIEDHBY 13 1925 3771; 924

SHEET 2 OF 4 PLANE E-E INV ENTOR ANTON BUCHSTALLER ATTORNEY ANTON BUCHSTALLER ATTORNEY PATENTEDNHV 1a 1975 31771, 924

SHEET REF 4 INVENTOI ANTON BUCHSTALLER BY 1 Z- 0 M ATTDRNEY COMBINATION GYROPLANE The present invention relates to a combination gyroplane the rotor of which is adapted to be locked in position and the rotor blades of which are retractable in that condition.

For combination gyroplanes of the aforementioned type which have the VT properties of a helicopter by virtue of one or several rotors, and means for producing the aerodynamic thrust during the cruising flight, it is necessary in order to reduce the drag to encase both the rotor head and the rotor blades with as little resistance as possible during cruising flight. As is already known in the art, this is achieved by folding the rotor blades into the back of the fuselage or into specific rotor nacelles which are mounted at the airfoil, for example. Particularly in the case of a larger number of rotor blades, there arise, in the heretofore known aircraft, large pivoting or retracting paths and considerable difficulties with regard to the hinged connection of the rotor blades. Also disadvantageous is an undesirable influence upon the cyclic blade displacement during the retracting operation.

The present invention provides a combination gyroplane in which the rotor blades can be retracted into a fairing at the aircraft in a simple manner and with as small a number of regulating units as possible, and specifically also in the case of rotors having a greater number of rotor blades.

The present invention also eliminates the cyclic blade displacement during the folding operation.

In accordance with the present invention, in each case the same number of rotor blades is mounted in at least two planes being offset with respect to each other with reference to the rotor axis, and a device is present which maintains the blade groups in a staggered arrangement and which causes the rotor blades of the aforementioned groups to overlap for the retracting operation.v

A combination gyroplane equipped as proposed by the present invention affords the advantage of a relatively simple construction, requiring only a limited number of structural elements, and the accommodation of the rotor blades in two planes being arranged at a distance from one another leads to smaller pivoting or retracting paths, as well as a simpler hinged connection and actuation of the foldable rotor blades. A further effect thereof is that the centrifugal forces are annulled due to balanced masses in the two planes of rotation. Any striking of the rotor blades against each other during the folding operation is prevented with certainty.

A further characteristic of the present invention is that the aforementioned device comprises at least two yoke parts mounted at the rotor axis which are rotatable with respect to each other and receive one group of rotor blades each. Another feature of the present invention is that one of the rotor blades of each group is rigidly connected, and the remaining rotor blades of each group are in a gimbal-type connection, with one of the yoke parts. The rotor blades of both groups can therefore be caused to overlap in a first pivoting-in or retracting phase by means of only a single regulating unit, and then will be changed from that position to a position in which all of the rotor blades are overlapping each other at least within the area of the blade tips.

According to a further embodiment of the present invention, it is proposed that the rotor blades being rigidly mounted at one of the yoke parts or portions be offset about a certain angular amount in one position of the yoke parts and that they be overlapping in a second position of the aforementioned yoke parts. This results in a significant simplication for the final retracting phase of the retracting operation of the rotor blades, with simplification is that the rotor blades being hingedly connected with the aid of gimbals to the yoke portions will be caused to assume an overlapping position with the rigidly mounted rotor blades that are already in the overlapping position, at which time easily controllable pivoting paths must be covered by the rotor blades. The relatively limited extent of the pivoting or folding paths to be covered also allows for a considerably simplified design of the adjusting linkage and of the adjusting drives, respectively.

One embodiment of the present invention is illustrated in the accompanying drawing, wherein FIG. 1 is a view in elevation of the rotor head,

FIG. 2 is a cross-sectional view of the rotor head according to FIG. 1, taken along line [1-1] in FIG. 1,

FIG. 3 is a further cross-sectional view through the rotor head taken along line III-III in FIG. 1,

FIG. 4 schematically illustrates and in a top plan view the rotor head together with the rotor blades, which latter are shown in the operative position thereof, and

FIGS. 5 to 7 show in schematic representations individual folding phases of the rotor blade folding operation in side views thereof.

In the rotor illustrated in the accompanying drawings, three rotor blades each are mounted in two superimposed planes. As has already been described hereinabove, the rotor in question is here the rotor of a combination gyroplane which has VTOL properties and which, in the horizontal flight, is adapted to fly aerodynamically borne with folded rotor blades and with the aid of lift surfaces. In the extended condition, all of the rotor blades will in this case be rigid. In the retracted condition, all of the rotor blades are positioned over each other.

Reference numeral 1 identifies the aircraft according to FIG. 4, and reference numeral la designates the retracting space within the fuselage of the airplane. Also, in FIGS. 1 to 4, reference numeral 3 identifies the rotor mast mounting, and reference numeral 4 identifies the rotor drive. Also provided are a lower and an upper swashplate 5 and 6, respectively, for the cyclic rotor blade displacement, as well as one control lever each 8 and 10, respectively, being coordinated to the two swashplates 5 and 6, respectively. The aircraft has moreover one setting device or mechanism for folding the rotor blades, which have been designated here with reference numerals 14 to 16 and, respectively, 17 to 19, in and/or out, as will be described in further detail hereafter.

More particularly, provided in known manner are a rotor mast 3 being rigid at the aircraft together with a rotatably positioned rotor axis 21 being arranged concentrically with respect thereto. The rotor axis 21 supports the upper and the lower swashplates 5 and 6 at a distance from each other. Each of the swashplates consists of two cooperating elements or portions 5' and 5" and 6' and 6". The elements or portions 5 and 6' are concomitantly rotatably held at the rotor axis 21 whereas the elements or portions 5" and 6 are secured in position against rotation. All of the elements of the upper and lower swashplates 5 and/or 6 are,

however, movably positioned by way of gimbals in the conventional manner for the cyclic blade displacement.

In FIGS. 1 to 4, the rotor blades are shown in the folded-out condition thereof, i.e. in the operative position. The rotor blades are combined into groups of three blades each 14, and 16 and 17, 18 and 19, and the rotor blade groups are positioned in planes of rotation EE and/or E'-E' being parallel or approximately parallel with respect to each other. The rotor blades of each blade group are supported by an upper and a lower yoke part and 26 mounted at the rotor axis 21, and the upper yoke portion 25 is connected with the rotor axis 21 so as to be rigid against rotation, whereas the lower yoke portion 26 is adapted to execute a limited relative rotation with respect to the upper yoke portion 25. For the purpose of allowing for the relative rotation of the yoke portions 25 and/or 26, a geared engine 28 with a drive shaft 29 and a pinion 30 being secured thereto is mounted at the yoke portion 25. The pinion 30 is in constant engagement with a toothed segment 31 which is secured to the lower yoke portion 26. Positioned between the upper and the lower yoke parts 25 and 26 are the stops 32 and 33 which cooperate at the end faces thereof and which, in the folded-out condition of the rotor blades, assume the transfer of torque from the rotor axis 21 to the yoke parts 25 and 26 while relieving the gear mechanism 30 and 31. The rotor blades of both planes EE and E'E are each positioned offset with respect to each other about 60 in the circumferential direction (FIG. 4). The rotor blades 14 and/or 17 being positioned each in one of the two planes of rotation EE and/or E'--E' assume, in the folded-out condition thereof, a position which is offset about 60 and are adjacent to each other. These rotor blades 14 and 17 are both rigidly mounted with respect to the yoke parts 25 and 26; they are, however, pivotal about their main axes for the cyclic blade angle displacement. The rotor blades 14 and 17 are held or supported by blade shafts 35 and 36, these shafts being rotatable about rigid articulated fittings 38 and 39. For the purpose of the rigid connection, two bolts 40 and 41 are provided by means of which the articulated fittings 38 and 39 are held at the respectively coordinated yoke parts 25 and 26. The remaining rotor blades 15, 16, 18 and 19 are held by means of blade shafts 42, 43, 44 and 45 and are rotatably supported against blade carriers 48, 49, and 51. By means of swivel pins 58, 59, and 61 which are positioned at a right angle with respect to the rotor axis 21, the blade carriers 48 to 51 are positioned at pivoting parts 53, 54, 55 and 56. The pivoting or swivel parts 53 and 54, and 55 and 56 are each supported by one yoke part 25 or 26 and are pivotal at the yoke parts 25 and 26 about axes parallel to the rotor axis 21. Positioned at both the rotor blade shafts 42 to 45 and also at the pivot or swivel parts 53 to 56 are projections between which there is mounted a double-acting control motor 62, 63, 64 and 65 consisting in each case of a piston and a cylinder. The pressure medium supply and control required for the control motors is designed and provided for in known manner and has therefore not been illustrated herein for the sake of simplicity. Between the hinged connections 68 and 69 at the concomitantly rotatable swashplate parts 5 and 6' of the upper and/or lower swashplates 5 and 6, and the hinged connections 70 and 71 at the rotor blade shafts 35, 36, 42, 43, 44 and 45, connecting rods 73 and 74 are arranged in known manner for purposes of the cyclic blade angle displacement. The connections 68 and 69 of the connecting rods 73 and 74 at the concomitantly rotatable swashplates 5' and 6' are so provided and arranged that the pivotal points are positioned in the imaginary extension of the pivot axes of the pivot parts 53 to 56. Inserted between the concomitantly rotatable swashplate parts 5' and 6' and the coordinated yoke part 25 and 26 is in each case a pair of steering knuckle arms 76 and 77 which establish a connection which is rigid against rotation between the yoke part 26 being rotatable on the rotor axis 21 and between the concomitantly rotatable swashplate part 6 of the lower swashplate 6 and, respectively, between the concomitantly rotatable swashplate part 5' of the upper swashplate 5 and the upper yoke parts 25 being connected with the rotor axis 21. The pairs of steering knuckle arms 76 and 77 do not transmit any forces in the direction of the rotor axis 21, and will therefore not impair the gimbal movements of the swashplates 5 and 6 for the cyclic blade angle displacement. The rotor axis 21 includes a brake disc 80 against which may be placed two brake shoes 81 and 82 being guided at the stationary housing. In the folded-out condition, i.e. in the working position, the rotor blades 14, 15 and 16 are positioned in a staggered arrangement, i.e., at a gap, with respect to the rotor blades 17, 18 and 19. In this position, all of the rotor blades are each offset with respect to each other about 60 with reference to the circumferential direction. In this case, the two rotor blades 14 and 17 being rigidly held at the respectively coordinated yoke part 25 and 26 will be adjacent each other.

As is apparent from FIGS. 2 and 3, there are further provided two double-acting control motors 85 and 86 and 87 and 88 each, which are pivotally supported against the yoke part 25 and against the yoke part 26, and which engage at the carriers 48, 49, 50 and 51, being adjacent the rotor blades 15, l6, l8 and 19, by way of one steering lever each 89 and 90, and, respectively, 91 and 92, and also by way of one connecting rod each 93 and 94 and, respectively, and 101.

The operation of the construction described hereinabove is as follows When the aircraft for example after a vertical takeoff has reached a speed at which a sufficient life is produced by the aerodynamically-acting means and a sufficient controllability is assured by means of the conventional control surfaces, the retracting operation for the rotor blades may be initiated.

For this purpose, the control motor 28 is turned on and, by way of the drive shaft 29 thereof as well as by way of the pinion 30 and the toothed segment 31, the lower yoke part 26 is rotated relative to the upper yoke part 25 and, respectively, the rotor axis 21, and specifically about an angular amount of 60. By virtue of this relative rotation, both the rigidly mounted rotor blades 14 and 17, and the hingedly connected rotor blades 18 and 15 as well as 19 and 16 of the upper and-lower blade group will come to be in an overlapping position.

During the relative movement of the yoke parts 25 and 26, the swashplate part 6' of the lower swashplate 6, being secured rigid against rotation at the rotor axis 21, will be concomitantly carried along by the yoke part 26 via the pair of steering levers 77 in the circumferential direction, while between the concomitantly rotatable part5' of the upper swashplate 5 and the upper yoke part 25 there exists a rigid coupling, with reference to the circumferential direction, via the pair of steering levers 76. The steering lever pairs render it possible for the swashplates 5 and 6 to execute the movements that are required for the cyclic blade displacement without hindrance.

As is apparent particularly from FIGS. 5 to 7, there also takes place, during the relative rotation of the yoke parts 25 and 26 with respect to each other, the actuation of the brush-shifting motors 62, 63, 64 and 65, and by means of the brush-shifting motors, a fan-like spreading of the hingedly-connected or Cardan-type connected rotor blades and 16 and 18 and 19 as compared to the respectively coordinated rigidly mounted rotor blades 14 and 17 (FIG. 5). As far as the rotor blade group is concerned which is positioned in the plane E-E, the rotor blade 15 is pivoted at that time upwardly from the position indicated in phantom (FIG. 5) and the rotor blade 16 is pivoted downwardly, while in the plane E'-E', the rotor blade 19 is pivoted upwardly in the same manner from the position indicated in phantom (FIG. 5), while the rotor blade 18 is pivoted downwardly. At the conclusion of the pivoting operation, the rotor blades of both groups will then be positioned so as to be spread apart in a fan-like fashion with respect to each other, as is apparent from FIG. 5. Due to the spreading, any striking of the rotor blades against each other and hence any impairment of the retracting operation are thus eliminated. The spreading angle of the rotor blades is here for example approximately 2.S as compared to the starting position. By means of the brake disc 80 at the rotor axis 21 and the brake shoes 81 and 82 at the stationary housing, the rotor axis 21 is defined in a position in which the two rigidly mounted, mutually overlapping rotor blades 14 and 17 will be positioned in the longitudinal central plane of the aircraft, i.e. in the flying direction.

After the spreading operation, the control motors 85, 86, 87 and 88 are actuated and the rotor blades 15 and 16 and 18 and 19 are pivoted about approximately 120 about the axes of the pivot of swivel parts 53, 54, 55 and 56. At the conclusion of the pivoting operation, the rotor blades of both groups will be positioned in an overlapping arrangement at least in the area of their blade tips and in the longitudinal central plane of the aircraft-(FIG. 6). Due to the fact that the pivotal points 68 and 69 of the connecting rods 73 and 74 for the cyclic blade displacement are positioned in the imaginary extension of the axes of the pivot or swivel parts 53 and 54 and 55 and 56, no undesired or unintentional cyclic displacement or the rotor blades will take place in any phase of either the pivoting of the rotor blades into their overlapping position or of the relative rotation of the yoke parts and 26.

From the pivoting-in position illustrated in FIG. 6, a renewed actuation of the brush-shifting motors 62 and 65 takes place, and specifically in a direction opposite to the spreading movement. All of the rotor blades 14 to 19 are thereby compressed using the rotor blade elasticity so that a blade package will result therefrom, as shown in FIG. 7, in which the rotor blades will rest against each other at least in the area of their blade tips. By means of the locking mechanism 102 (FIG. 7), the rotor blades are held in this position and the flapping hinge control motors 62 and 65 are switched off. In this position, the rotor blades can be enclosed with foldable fairing parts at the aircraft (not shown) for reducing the aerodynamic drag during the flying phase in which the aircraft is borne aerodynamically.

The construction proposed by the present invention is not limited to the number of rotor blades disclosed in the present embodiment, but may be equally applied to an either greater or smaller number of rotor blades.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

I claim:

1. In a combination gyroplane having a rotor mast and rotor blades adapted to be retracted, the improve ment which comprises an equal number of rotor blades positioned in at least two planes offset with respect to each other with reference to the rotor axis,

a pair of yoke means supporting said blades on said rotor mast and being capable of limited rotation relative to each other, and

one blade of each group being non-pivotally secured to said yoke means and the remainder of said blades being pivotal about axes substantially parallel to the rotor axis.

2. A gyroplane according to claim 1 in which one of the yoke parts is rigidly secured against rotation with the rotor axis and the second yoke part is relatively rotatable with respect to the rotor axis and the other yoke part.

3. A gyroplane according to claim 2 including lock-in connection means between swash plate means and a relatively movable yoke part in the circumferential direction.

4. A gyroplane according to claim 1 in which one each of the rotor blades of each group is rigidly connected and the remaining rotor blades of each group are connected by means of a Cardan connection with one of the yoke parts.

5. A gyroplane according to claim 4 in which the rotor blades being rigidly mounted at one each of the yoke parts are positioned offset by an angular value at one position of the yoke parts and overlap in the second position of the yoke parts.

6. A gyroplane according to claim 5 including means for securing the rotor in a position in which the rigidly mounted rotor blades have assumed the overlapping position and are positioned in the longitudinal central plane of the aircraft.

7. A gyroplane according to claim 1 including one swash plate means each for the cyclic rotor blade displacement for each of the blade groups.

8. A gyroplane according to claim 7 in which pivotal points for connecting rods for the cyclic rotor blade displacement are positioned at the concomitantly rotatable swash plate part in the imaginary extension of the axis of rotation of a pivot means.

9. A gyroplane according to claim 4 in which carriers for the Cardanically-connected rotor blades are secured by means of brush shifting motors and pairs of steering means.

10. A gyroplane according to claim 9 including pivot means for moving the Cardanically movable rotor blades out of their operativeposition into a position in which all of the rotor blades overlap each other.

11. A gyroplane according to claim 9 including brush shifting motors for displacing the Cardanicallyconnected rotor blades for purposes of the retracting operation.

12. A gyroplane according to claim 9 including brush shifting motors for pressing the rotor blades against each other in the folded position and including means for locking the folded blades in position.

* r a s s 

1. In a combination gyroplane having a rotor mast and rotor blades adapted to be retracted, the improvement which comprises an equal number of rotor blades positioned in at least two planes offset with respect to each other with reference to the rotor axis, a pair of yoke means supporting said blades on said rotor mast and being capable of limited rotation relative to each other, and one blade of each group being non-pivotally secured to said yoke means and the remainder of said blades being pivotal about axes substantially parallel to the rotor axis.
 2. A gyroplane according to claim 1 in which one of the yoke parts is rigidly secured against rotation with the rotor axis and the second yoke part is relatively rotatable with respect to the rotor axis and the other yoke part.
 3. A gyroplane according to claim 2 including lock-in connection means between swash plate means and a relatively movable yoke part in the circumferential direction.
 4. A gyroplane according to claim 1 in which one each of the rotor blades of each group is rigidly connected and the remaining rotor blades of each group are connected by means of a Cardan connection with one of the yoke parts.
 5. A gyroplane according to claim 4 in which the rotor blades being rigidly mounted at one each of the yoke parts are positioned offset by an angular value at one position of the yoke parts and overlap in the second position of the yoke parts.
 6. A gyroplane according to claim 5 including means for securing the rotor in a position in which the rigidly mounted rotor blades have assumed the overlapping position and are positioned in the longitudinal central plane of the aircraft.
 7. A gyroplane according to claim 1 including one swash plate means each for the cyclic rotor blade displacement for each of the blade groups.
 8. A gyroplane according to claim 7 in which pivotal points for connecting rods for the cyclic rotor blade displacement are positioned at the concomitantly rotatable swash plate part in the imaginary extension of the axis of rotation of a pivot means.
 9. A gyroplane according to claim 4 in which carriers for the Cardanically-connected rotor blades are secured by means of brush shifting motors and pairs of steering means.
 10. A gyroplane according to claim 9 including pivot means for moving the Cardanically movable rotor blades out of their operative position into a position in which all of the rotor blades overlap each other.
 11. A gyroplane according to claim 9 including brush shifting motors for displacing the Cardanically-connected rotor blades for purposes of the retracting operation.
 12. A gyroplane according to claim 9 including brush shifting motors for pressing the rotor blades against each other in the folded position and including means for locking the folded blades in position. 